serotonin and sleep

A question I have always wondered, they say serotonin helps sleep, but why when alot of people take ssri's that raise serotonin, it causes insomnia or worsens insomnia? Even when using it for long periods. 5htp has never done anything for me either way.

u sound similar to me sleep wise. I cant take anything more then twice in a row and it stops working. I rotate between a few things, my 2 favourite compo's are doxepin 50mg/valium 10mg twice/week, the other seroquel 100mg with 150mg lyrica once/week. I use these combos sparringly as its good restorative sleep. The rest of the time its zopiclone or antihistamines and herbal stuff.

I was just wondering about ssri's as in the past have found them good for mood and cognitive energy but bad for sleep, although have read where after a few weeks they help sleep, not in my case. Have read that drugs that block 5ht2a can be used to overcome insomnia of ssri's. 5ht2a antagonists eg avanza, seroquel, periactin (cheap over the counter antihistamine), maybe phenergan, trazodone. So trying to get alist and see what i can maybe take with a low dose of zoloft like 12.5-25mg.